Method of reduction of esters, etholides, glycerides



Patented Aug. 26, 1952 STAT-Es PATENT oFFice;;

asoassa r METHOD OF REDUCTION OF ESTERS, ,ETHOLIDES, GLYCERIDES PaulAnglaret, villeDfavray, France No Drawing. Application June 27, 1947,Serial No.757,661. InFranceJuly 5,1946

This invention relates to, the reduction of esters, etholides,glycerides (glycerinefesters), nitriles (alkyl cyanides) and the like.The method of the invention is particularly useful in the prov ductionof higher alcohols.

sponding' tothe acidof the ester is by the use of sodium andan alcohol.

V However, this process often allows only a poor recovery of the alcohol(60 to 80 Various patents, that claim to give good re- Z. fsults,advocateworkingunder vacuum, under hydrogen pressure, or Ebyadding theester alcohol mixture in theoretical amount, to the sodium dissolved inasuitable solvent. These processes,

h .lhowev'er, arenever satisfactory as far as quantities (yields) areconcerned, and exhibit various drawbacks in their procedure (use ofpressure,

. vacuum, exceptional. dissolving agents). More- ,over, the possibleglycerine recovery and the con- I tinuous operation are difficult.

.The improvement introducedby this inven tion has as its main featurethe decomposition of the alcoholate formed in the reaction, by

'1 means of. either one ,of two reagentswhich do not themselves reactupon the sodium as such, under the conditions present in. the reactionmass. But these reagents are..capable,-however, of regenerating thealcohol from the alcoholate, and act to precipitate the sodium in theform of a I salt of high sodium content and which salt, how- 7, ever,does not add substantially to the viscosity of the solution. The amountof alcohol in question is thus recovered in a satisfactory quantity,theidecompositi'on of thealcoholate'eliminating all secondary reactionthat mightprove detrimental to this result. 7

l According. to the reagent and alcohol em- 01 solution and a definiteworking procedure mustbe put into servicein order, on the one han'd, toreach without difficulty theoutput required and, on the other handjtouse only the minimum amount of sodium.

Moreover, whe'nthe operation is conducted in r alcoholicsolution; theuse of any'solvent, other than'the alcohol, ca'nbe avoided. The sodiumin small lumpsfcairbeadded to the liquidesteralcohol mixture. Thetreatment is carried out atnormal'atmospheric pressure.

r The process can be adapted to the same materials as the standardmethod of Bouveaul-t and --Blanc: 1; ,Thedecomposition of the alcoholateunder the conditions indicated, which constitute 'the main object ofthis invention, can beeifected in various ways and by varioussubstances. 1

As a guide and notin any way binding, mention may be made especially ofsalts with acid I reaction, e. g. NHsCl, acid anh'ydrides, e. g. CO2,

., fIthasbeen common knowledge tor a long time jthatthe only way for thechemical reductionof esters. for. the (production of "the'jalcoholcorre- 5 Claims. (011260- 63 organic substances that can give variouscondensations with the alcoholates,- .forinstance,

chlorinated compounds in which the chlorine is especially unstable;substances that are ableto fconvert the alcoholate merely by additivereaction. The ammonium salts which react upon the (R is the hydrocarbonradical or, the alcohol falcoholate can give a reaction expressed asfollows, in case X is a monovalent acid radical: NH4X+NaOR=NaX+ROH+NH3which with sodium forms sodium alcoholate,

e. g. -'C4H9). The acid radical can be ,-.-Cl,"in the case of ammoniumchloride. The salts formed do nothave more thanavery slight solubilityin the alcohols.

, The C02 reacts with the alcoholatathusi COz'-|-NaOR- NaRCO3 and theaddition of water causes the following reaction:

ZNaRCQ3+HzOr+CO3Nag+CO2+2ROH The salts formed do not have more than avery slight solubility in the lower alcohols; thus,

COsNaz is practically insoluble in butyl :alcohol. Generally speaking,it will be possible'to use for this procedure all substancesable toensure,

by a particular reaction, the decomposition oi the alcoholate, that,ifpresent, is positively harmful for a satisfactory recovery in anyamount as a result of the reaction. These bodies, however, under theconditions in which they are 1 applied, must not give any secondaryreactions ployed, an enact. degree of temperature, strength a with thesubstances usually present or produced during the reaction (ester;alcohol, sodium, nascent hydrogen) and the conversion of the alcoholatemust proceed at asatisfactory rate.

Other advantages of the process are presented by the possibility thatthe process can be made continuous, the complete recovery of theglycerine, the complete security and speed .of the process.

The following examples ofrperformance of this invention :may besubmitted as a; guide without any restricting clauses.

Example I.-'Chemical agent for the decomposiing sodium butylate, i. e.l-v I 3 washed. with hot water. '.;,'The; hot watenidissolves.

,fthesodium chlOride .andthe glycerine. liberated "I l QIIi th8 whale"oil,,in"the process. The. recovery of 'EIYCErinefj-frorri f the salinesolution; is. an ,.easy

matter.

'I'hairesultingrproductrhigheralcohol produced by the reduction. of.the, fattyacids of 1 the whale ,1, l and. falsd higher. jalcohoLproducedby ,saponi- ,jfficati'on jofjffihc whaleoil (which is partly glycerideesters of higher llfatty ecidsu, and. partlyesters pf higher ,monoh dricfalcoholsflwith; such,.fatty =-acids consists of..90 gr;that,after-treatment' witna, :few. drops. .of. hydrochloric, acid,Washing and "drying, has acidity value: A.V.:1.5,

S.V.:3.5, Nil-67, ---hydroxyl value: H.V.:224. 2he:ov.era11 reactioncanbe expressed in, a simple "condensed form, as' follows:

11in": which -efloQR" :is the :fatty:;.acid '(or r acids) nfrtheiwhale'zoil: (which is; a mixture ot'esters) s'anci ltheyalkyl-residue:of such .esters whether rmonohydriczorz-trihydric) rE'idmnll I I-,C.hemiocZ reqgent used 'for; decomposition alcoholatel and.precipitation. of the ssodium .-=as Yd salt; Carbon dioxide (CO2 withH20.)

- :In='a bal1oon-flash'of 1.5 litres capacity-and of#:suit'able-:shape,-' is added ZOO-gr. of butyl oleate andi400 :to 60OgIuOf butanol'lbutyl alcohol). Carbon idioxide is beaten into thesolution' by means ci a-perforated hollow agitator 66- gr. of sodium.(an excess oi -25%) cut up into pieces of i less ithaniz gr. 'eachisadded gradually. ,The itemperature, startingat 80 rises steadily so l'aSl-tO IBaCh the boilingpoint ofthe" mixtureat the end of the reaction.Water is added by ..::degrees".in' some. suitable- "shape (forinstance,ehydrated mineral salts so'that the mixture preserves a slight degree ofviscosity. Itwillbe durideljstood ..-that thehydrated mineral-salts will-'1he ssuch as idq, not react unfavorably with any of the substances inthe mixture. .Crystallized sodium carbonate decahydrate would beentirelysuitable.

-' The' butanol lbutylalcohol) is'ior" themost part car'ried off bythecurrent of'COz.

' P -After the last-piece of sodium -is -adde d, 'the :remaining butanolis: distilled. v Enough hot water 'iswaddedto dissolve the sodiumcarbonate formed. The layer of' 'oleic alcohol that separates outtreated witha few-drops of hydrochloric-acid, hen? washed until it isquite neutral; and dried. xiThe resultant: product :consists of 155 gr.ex- "raliibi ingzthe. followin characteristics: S;V;:3, A-.V:.:0.8,I'.V.=,8.0;:;hydroxyl value H.Y.;;1-I99.

1 gfta 'continuous basis.

Qnrtreatingtrape-seedilzinithersame manner (S=V:=1 iI.V.=105,;5AM.-=Ii0.4) there is produced a product showing values:S.V.=:

this case it is necessary to add 40% excess of 4 wsodiumybe'cause theglycerine formed reacts on When the ammonium chloride reacts with "the"th'e sodium with partial loss of the latter. The recovery ofrtheglycerine presents no difficulty. These processes are capable of beingplaced on For instance, by working with-ammonium chloride added, theestablish- ..mentias a continuous procedure of Example No.

1 may be conducted in the following way:

.JlZhe. operationtakes; place .in.,a...horizontal..tube, l6withitheiagltatorfiformediibyaar secondrtubenra a volving at highspeedinsidejjtheifirstrt'ube. .ZSev- .era1f' i(n)1-tubes. in series,.are;ne'eded.. 1' /n: 'otithe required amount of sodium'isadded',.,1atthejront rend. of each tube} in pieces of whichithe.',diameter 20., is. slightly? 'lesstjthan the difference; .of the:radii rofgtube and agitator. Theester-butanol mixture with its.contentsof'all .theiammo'nium chloride is added at'th'e front end'ofthejflrst tube. p

.Between the outlet end.of-a;tube and;'inlet end oftheizfollowinggtubaia;portion of the butanol. is, distilled, so that',atxthe" end of "the procedure the; greater; portion or the butanol hasbeen removed. The: amounts'of reagents us'ed are nearly the same as inthe mun-continuous ,experimental run' '(i. e. iniilxample I). 1

' j The "temperature of ..the first tube "is 80 1'11 ".lthe other;tribes have successivelyx higher; tem- ..peratures, with temperaturesiinlthei': last'ttiibe p'at;110..C.

Thenumberlof' tubes is: afactor of. the W il ht of sodium piecesiithatgthe-"size" of "the" apparatus allows to be .added. Theigreater'.the sizejofthe apparatus, irthe smaller the *qrnumber of "tubesrequired. j

40 10h. exit from the-lasttube;"'the"norm'al work of 'distilling'ris'carried out, with :washingr and decanting by continuous standardmethods.

"It may be observed thatthe starting mixture may j be obtained "directly{by "bringing in the ammonia;gas es and; hydrochloriczacid gas'into theesterebutanol mixture, soithathydrochloric acid :and sodium are-the:only reagentspsed up.

' The results Obtained-are asj ood .as in thenoncontinuous process.

.flIt will thus be seen that the' inventioir relates to '1 improvementsin fthe reduction of "esters, etholides, glycerides; nitriles, 'etc.,by; means of an alkali metal, such as sodium;.and;an"alcohol;.characterized by .the;:fact that alkali metal alco- "..ho1ate producedby-a sidereacti'on is decomposed.

"By decomposing the alcoh'olate objectionable sec- ;onda reactionsare-prevented. c 'Due 'to thef' 'decomposition .of] the Ialcoholate'jit,, is rendered harmless in the working of'the process.

The following additionalpexamples may balconfljsijdered; "They dealespeciallywithi nprovements in recoveries; lowerin of thezamou'nt oflower alcohol, such .as'. but l alcohol,- used'iand .thcrre-.ilduc'tionof nitrilesxalkyl cyanides). v ExampleIII.-.-;R.educticn;;ofrr:steanic:nitrile -Ammoniumchloride in-excess isadded-to the stearic nitrile dissolved in butyl iilcoliol. With thetemperature kept at about 80 C. the tli'em retical it amount of sodium=is -added gradually, to givethen -ami'xed product, 'of="70%a ofsecondary amines or' amino-bases, 'gand"; 2ll-% of -primary amines orim'in'o' bases. a Example.iIvrlahReduction-nfiflur butyl oleate J;Into:a. .ballooneflaskr furnished withwsalecondenser, is placed 100 grams ofbutanol (butyl a1- cohol) and a fractional proportion to A) of the totalamount (l50 gr. for the particular example) of the butyl oleate to bereduced; about 55 gr. of sodium is added very slowly so that the totaladdition spreads over a period of several hours; for this reason, thereliability of the procedure is substantially increased in relation toother known methods.

After 1.5 gr. of sodium has been introduced, a continuous flow of wateris directed into the mixture through the upper end of the condenser, sothat the amount of water which has been added up to any instant duringthe reaction is slightly less than th theoretical amount required basedon the amount of sodium which has been added up to that instant. Theaddition of water is continued until substantially the theoreticalquantity (21 gr.) has been added. The overall reaction can be expressedas follows:

(RCO2C4H9 denotes butyl oleate) During this operation carbon dioxide andwater are added in the respectiv required amount.

In the same way, the remainder of the oleate sodium carbonate formed;this can be done without any risk as the sodium has been completelyconverted; then the organic layer is decanted off and the butanol isseparated out by distillation; thus the recovery is about 99.5%.

By means of a further distillation, about 112 to 113 gr. of pure oleicalcohol is obtained, thus giving a final recovery in the region of 98%,

(b) This working technique can be applied to glycerides (glycerineesters). For instance, with palm kernel oil, if the product of reaction,after removal of sodium carbonate and butanol, is treated with a littlehydrochloric acid, then washed until neutral to litmus paper, the resultobtained, in theoretical amount, is a crude product exhibiting thefollowing values:

Acidity value=1 Saponification value=7 Iodine value=22 Hydroxylvalue=268 This last technique has the advantage over the previousexamples by bringing into play only slight amounts of butanol, whileallowing recovery of the glycerine to proceed.

The invention offers a number of advantages: When starting withchemically pure products, it is possible to obtain a recovery of about99.5% of the crude end product. If desired, a recovery in theneighborhood of 98% of pure fatty alcohol (e. g., oleic alcohol) may beobtained by distillation. The amount of lower alcohol, such as fattyacid with metallic sodium and a lower aliphatic alcohol with resultantformation of a, sodium alcoholate, the improvement which comprises:carrying out said reaction at substantially atmospheric pressure; duringsaid reaction, decomposing the sodium alcoholate substantially as fastas it is formed and regenerating said aliphatic alcohol by adding duringsaid reaction ammonium chloride; and maintaining during said reaction atemperature between about C. and the boiling temperature of the mixtureof react ants and reaction product.

2. In a method for the production of higher alcohol by the reaction ofan ester of a higher fatty acid with metallic sodium and a loweraliphatic alcohol with resultant formation of a sodium alcoholate, theimprovement which comprises: carrying out said reaction at substantiallyatmospheric pressure; during said reaction, decomposing the sodiumalcoholate substantially as fast as it is formed and regenerating saidaliphatic alcohol by adding during said reaction ammonium chloride; andmaintaining during said reaction a temperature between about 80 C. andthe boiling temperature of the mixture of reactants and reactionproduct, whereby the sodium. salt produced by said reaction issubstantially noncolloidal, is substantially insoluble in said loweraliphatic alcohol, has a high sodium content and does not materiallyincrease the viscosity of the mixture of products of said reaction.

3. In a method for the production of higher alcohol by the reaction ofan ester of a higher fatty acid with metallic sodium and a loweraliphatic alcohol with resultant formation of a sodium alcoholate, theimprovement which comprises: carrying out said reaction atsub-stantially atmospheric pressure; during said reaction, decomposingthe sodium alcoholate substantially as fast a it is formed, andregenerating said aliphatic alcohol by adding during said reactionammonium chloride; and maintaining during said reaction a temperaturebetween about 80 C. and the boiling temperature of the mixture ofreactants and reaction product, thereby forming a non-viscous reactionproduct comprising said higher alcohol, unreacted portions of said loweraliphatic alcohol, and a non-colloidal sodium salt having a high sodiumcontent, and insoluble in said lower aliphatic alcohol.

4. A method according to claim 3 further comprising separating saidsodium salt and unreacted lower alcohol from said reaction product, andforming by said separation a residue containing said higher alcohol.

5. A method according to claim 4, further comprising recovering asubstantially pure higher alcohol from said residue.

PAUL AN GLARET.

REFERENCES CITED The following references are of record in the file ofthis patent:

Organic Synthesis, Collective Vol. II, Reid et al., John Wiley and Sons,N. Y., pages 468-470 (1943).

Number Anglaret et al., Compte Rendu, vol. 223, pages

1. IN A METHOD FOR THE PRODUCTION OF HIGHER ALCOHOL BY THE REACTION OFAN ESTER OF A HIGHER FATTY ACID WITH METALLIC SODIUM AND A LOWERALIPHATIC ALCOHOL WITH RESULTANT FORMATION OF A SODIUM ALCOHALATE, THEIMPROVEMENT WHICH COMPRISES: CARRYING OUT SAID REACTION AT SUBSTANTIALLYATMOSPHERIC PRESSURE: DURING SAID REACTION, DECOMPOSING THE SODIUMALCOHOLATE SUBSTANTIALLY AS FAST AS IT IS FORMED AND REGENATING SAIDALIPHATIC ALCOHOL BY ADDING DURING SAID REACTION AMMONIUM CHLORIDE; ANDMAINTAINING DURING SAID REACTION A TEMPERATURE BETWEEN ABOUT 80* C. ANDTHE BOILING TEMPERATURE OF THE MIXTURE OF REACTANTS AND REACTIONPRODUCT.